Nathaniel Fujita faces life in prison without parole if he's convicted in the death of his former girlfriend, Lauren Astley. Fujita’s lawyer will likely argue that the 20-year-old was insane at the time of Astley’s death.

Manley said as investigators searched Fujita’s home, he did not suspect the teen. Manley described him as "calm, stable" with nothing to indicate he was "angered or frustrated."

In their opening statements last week, prosecutors said Fujita’s actions were deliberate. They pointed to evidence of a specific search on his computer.

“Does water erase finger prints? I ask you when you hear that not only to think about the implications for what he did, but think about the implications for how his mind was working and what his intentions were,” prosecutor Lisa McGovern said.

Lawyers for Boston Marathon bomber Dzkokhar Tsarnaev rested their case in his federal death penalty trial Tuesday after presenting a brief case aimed at showing his late older brother was the mastermind of the 2013 terror attack.